A new study has revealed that bacteria living in the human gut could affect the way cancer drugs work.

Research conducted at the University of Texas shows that certain types of bacteria living deep inside the gut can improve the efficacy of a form of treatment known as immunotherapy. Immunotherapy is one of the most exciting cancer treatment developments and it works by altering the body’s own defence system to tackle and destroy tumours. The drugs, in effect, reinvigorate the immune system, encouraging it to fight cancerous cells and remember them in the future, if cancer returns.

Researchers in Texas conducted a study on a small group of participants to see how they reacted to immunotherapy. The group included 23 patients who had responded positively to treatment and 11 who had not. Dr Jennifer Wargo explained that faecal samples showed differences in the diversity of bacterial species found in those who responded positively and those who showed no improvement following immunotherapy. The team found significantly higher levels of a strain of bacterium known as ruminococcus in patients who responded to immunotherapy.

The findings of the study have been discussed at the National Cancer Institute’s Cancer Conference in Liverpool and the study has attracted interest from researchers in the UK. Dr Wargo believes that the team in onto something and suggests that altering the balance of bacteria in the gut could contribute to a positive outcome.

Sir Harpal Kumar, Cancer Research UK’s chief executive, said that we are only “scratching the surface” when it comes to understanding the role of trillions of bacteria living in the body and this study certainly provides food for thought. He described the findings as interesting and exciting and hopes that further research will help patients to respond to treatment more positively in the future.